In a method of manufacturing a molded article by curing a resin composition, a molded article in a desired shape is required to be obtained, by sufficiently suppressing warpage and the like that occur at the time of curing the resin composition. When a molded article to be manufactured has a relatively large area, that is, when the ratio of the area to the thickness is relatively large, there is a tendency that the occurrence of warpage becomes noticeable. Therefore, a method in which, even when a molded article of a relatively large area is to be manufactured, the occurrence of warpage can be sufficiently suppressed when curing a resin composition, is required. Specifically, when manufacturing the following semiconductor package, the above-described method of manufacturing a molded article, the warpage of which is suppressed, has come to be required.
As semiconductor packages, ball grid arrays (BGA) of a wire bond type and a flip chip type are being used. On the other hand, in order to solve new problems that occur associated with quality improvement of electronic devices, further quality improvement such as high-density wiring, high functionalization, downsizing and thinning, and high speed while suppressing the excessive increase in cost is required for semiconductor packages that are used in electronic devices. Specifically, the wire bond type BGA, for example, has problems in high cost because of use of metal wires, difficulty in miniaturization, reduction in reliability due to wire sweep, etc. The flip chip type BGA has a shorter connection distance between the electrode of a semiconductor chip and the circuit of a substrate as compared with the wire bond type, and therefore, has advantages in that the electric characteristic is satisfactory and the package can be made compact. However, even in the case of the flip chip type BGA, multiple pinning (multiple I/O) following the miniaturization is required to satisfy the above further requirements. Consequently, further miniaturization of a solder bump and cost increase in corresponding interposers have become problems.
As a new mode of a semiconductor package that is manufactured without using a wire bond, a solder bump, or interposers, there has been proposed a wafer level package (WLP) of carrying out packaging while still part of the wafer. As an example of a WLP, a wafer level chip size package (WL-CSP) is available.
The WL-CSP is a package obtained by performing not only electrode forming but also resin sealing and the like and finally by cutting to provide chips, in a wafer process. Because the size of the WL-CSP finally obtained by cutting a wafer directly becomes a size of the package, the WL-CSP can be said to be ideal from the viewpoint of downsizing and weight reduction. However, according to the WL-CSP, because the package size is determined by the size of the semiconductor chip, there is a limit to the increase in the number of I/O.
Therefore, a fan-out type WLP (fan-out WLP: FOWLP) has been proposed. In order to satisfy the multiple pinning (multiple I/O) requirement, the FOWLP is a package obtained by arranging a plurality of individual semiconductor chips on a supporting medium which is removed later, and by performing resin sealing and subsequent cutting of the semiconductor chips. Therefore, as resin sealing methods when manufacturing the FOWLP, for example, there is a method of covering a supporting medium on which a plurality of semiconductor chips are mounted, using a resin composition as a sealing material, and curing the resin composition. In the case of this method, the area of covering the semiconductor chips with the resin composition becomes relatively large. When the resin composition of such a relatively large area was cured, there was a tendency that warpage and the like easily occurred, as described above. Therefore, as resin sealing methods when manufacturing the FOWLP, there has been demanded a method of obtaining a molded article in which the occurrence of warpage and the like when curing the resin composition is sufficiently suppressed even when the molded article has a relatively large area. When the area of an obtained molded article becomes large, a contact area between the supporting medium and the molded article becomes large, and therefore, there has also been a problem in that peeling of the molded article from the supporting medium becomes difficult.
As a method of manufacturing such a semiconductor package, there is one described in US Patent Application Publication No. 2006/0183269 (hereinafter Patent Document 1).
Patent Document 1 describes a method using a temperature sensitive adhesive which loses adhesion performance at or above a predetermined temperature. Specifically, the described manufacturing method of a semiconductor package includes arranging a plurality of semiconductor chips at a temperature sensitive adhesive side, of a supporting medium having the temperature sensitive adhesive on the surface, embedding the arranged semiconductor chips with a plastic material, thereafter heating the embedded semiconductor chips at or above a predetermined temperature to lose adhesion performance of the temperature sensitive adhesive, and peeling the supporting medium.
According to studies by the present inventors, when manufacturing a molded article including a cured product of a resin composition on the supporting to be finally peeled, there has been a problem in that the supporting medium is hard and cannot be bent. That is, when what is called a rigid substrate is used, after the molded article is formed on the supporting medium, at the time of peeling the molded article from the supporting medium, the molded article is damaged, and the molded article in a desired shape cannot be obtained. Further, there is a problem in that when the molded article contains semiconductor chips, stress is applied to the semiconductor chips themselves at the peeling time, so that the semiconductor chips are damaged and a crack occurs due to stress applied to the semiconductor chips and the resin interface.
When what is called a bendable flexible substrate is used as a supporting medium, there has been a case where warpage that occurs at the time of curing a resin composition cannot be sufficiently suppressed, on the supporting medium. That is, there has been a case where the obtained molded article was a warped product. When semiconductor chips are contained in the molded article, there is also a problem in that stress is applied to the semiconductor chips and the resin interface and a crack occurs due to warpage.
Such a damage to the semiconductor chips becomes a cause of that the semiconductor chips subsequently do not correctly function as electronic parts. On the other hand, a crack on the semiconductor chips and the resin interface can become a cause of that an insulation resin layer cannot be uniformly formed at the time of forming the insulation resin layer on the semiconductor chip circuit surface to form an electric wiring later, and that molding performance of the electric wiring is aggravated.
According to the method described in Patent Document 1, when a rigid substrate is used as a supporting medium, the occurrence of warpage can be suppressed, and the adhesion performance is lost by heating. Therefore, the problem at the peeling time is not considered to easily occur.
However, at the time of curing the resin composition to be used to seal the semiconductor chips, there is a risk that the adhesion performance of the temperature sensitive adhesive becomes low. Further, in order to suppress the reduction in the adhesion performance of the temperature sensitive adhesive, the resin composition needs to be cured at a temperature lower by a certain level than a temperature at which the adhesion performance of the temperature sensitive adhesive becomes low. Therefore, there has been a problem in that material selectivity of the resin composition to be used to seal the semiconductor chips became low. Further, according to the method described in Patent Document 1, after the resin was cured, the resin was necessary to be heated to a temperature at which the adhesion performance of the temperature sensitive adhesive became low. That is, there is a problem in that the number of processes becomes large because the heating process needs to be executed at two times. Further, when an adhesive having no temperature sensitivity was used, there has been a problem in that the molded article was damaged at the time of peeling the molded article from the supporting medium.
The present invention has been made in view of the above circumstance. An object of the invention is to provide a manufacturing method of a molded article capable of manufacturing a molded article in a desired shape, by reducing problems of selectivity of a resin composition, by suppressing warpage of a resin molded article without giving a damage to the resin molded article and contained substances such as semiconductor chips and electronic parts, even in the case of manufacturing a molded article having a large area.